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Query: EC:4.1.99.3 (
PRE
)
1,923
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Pseudomonas putida
KT2440 retains three homologs (PplR1 to PplR3) of the LitR/CarH family, an adenosyl B
12
-dependent light-sensitive MerR family transcriptional regulator. Transcriptome analysis revealed the existence of a number of photoinducible genes, including
pplR1
,
phrB
(encoding
DNA photolyase
),
ufaM
(furan-containing fatty acid synthase),
folE
(GTP cyclohydrolase I),
cryB
(cryptochrome-like protein), and multiple genes without annotated/known function. Transcriptional analysis by quantitative reverse transcription-PCR with knockout mutants of
pplR1
to
pplR3
showed that a triple knockout completely abolished the light-inducible transcription in
P. putida
, which indicates the occurrence of ternary regulation of PplR proteins. A DNase I footprint assay showed that PplR1 protein specifically binds to the promoter regions of light-inducible genes, suggesting a consensus PplR1-binding direct repeat, 5'-T(G/A)TACAN
12
TGTA(C/T)
A-3
'. The disruption of B
12
biosynthesis cluster did not affect the light-inducible transcription; however, disruption of
ppSB1-LOV
(where LOV indicates "light, oxygen, or voltage") and
ppSB2-LOV
, encoding blue light photoreceptors adjacently located to
pplR3
and
pplR2
, respectively, led to the complete loss of light-inducible transcription. Overall, the results suggest that the three PplRs and two PpSB-LOVs cooperatively regulate the light-inducible gene expression. The wide distribution of the
pplR
/
ppSB-LOV
cognate pair homologs in
Pseudomonas
spp. and related bacteria suggests that the response and adaptation to light are similarly regulated in the group of nonphototrophic bacteria.
IMPORTANCE
The LitR/CarH family is a new group of photosensor homologous to MerR-type transcriptional regulators. Proteins of this family are distributed to various nonphototrophic bacteria and grouped into at least five classes (I to V).
Pseudomonas putida
retaining three class II LitR proteins exhibited a genome-wide response to light. All three paralogs were functional and mediated photodependent activation of promoters directing the transcription of light-induced genes or operons. Two LOV (light, oxygen, or voltage) domain proteins, adjacently encoded by two
litR
genes, were also essential for the photodependent transcriptional control. Despite the difference in light-sensing mechanisms, the DNA binding consensus of class II LitR [T(G/A)TA(C/T)A] was the same as that of class I. This is the first study showing the actual involvement of class II LitR in light-induced transcription.
...
PMID:Light Response of
Pseudomonas putida
KT2440 Mediated by Class II LitR, a Photosensor Homolog. 3296 8
